scholarly journals Folate metabolism modifies chromosomal damage induced by 1,3-butadiene: results from a match-up study in China and in vitro experiments

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Menglong Xiang ◽  
Zhi Wang ◽  
Peng Zou ◽  
Xi Ling ◽  
Guowei Zhang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Methylenetetrahydrofolate Reductase ◽  
Micronucleus Assay ◽  
Folate Metabolism ◽  
Global Dna Methylation ◽  
Dependent Manner ◽  
Chromosomal Damage ◽  
Dna Hypomethylation ◽  
Exposed Workers ◽  
Tk6 Cells

Abstract Objectives To explore the role of folate metabolism in 1,3-Butadiene (BD)'s genotoxicity, we conducted a match-up study in BD-exposed workers in China to analyze the associations between the polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and the chromosomal damage induced by BD exposure, and culture-based experiments in TK-6 cells to examine the global DNA methylation levels and chromosomal damage when exposed both to BD’s genotoxic metabolite, 1,2:3,4-diepoxybutane (DEB), and MTHFR’s direct catalytic product, 5-methyltetrahydrofolate (5-MTHF). Methods Cytokinesis block micronucleus assay (CBMN) was used to examine the chromosomal damage induced by BD or DEB. Poisson regression models were produced to quantify the relationship of chromosomal damage and genetic polymorphisms in the BD-exposed workers. Global DNA methylation levels in TK6 cells were examined using DNA Methylation Quantification Kit. Results We found that BD-exposed workers carrying MTHFR C677T CC (2.00 ± 2.00‰) (FR = 0.36, 95%CI: 0.20–0.67, P < 0.01) or MTHFR C677T CT (2.87 ± 1.98‰) (FR = 0.49, 95%CI: 0.32–0.77, P < 0.01) genotypes had significantly lower nuclear bud (NBUD) frequencies than those carrying genotype MTHFR 677 TT (5.33 ± 2.60‰), respectively. The results in TK6 cells showed that there was a significant increment in frequencies of micronucleus (MN), nucleoplasmic bridge (NPB) and nuclear bud (NBUD) with exposure to DEB at each 5-MTHF dose (ANOVA, P < 0.01). Additionally, there was a significant decrease in frequencies of MN, NPB and NBUD in DEB-exposed cultures with increasing concentration of 5-MTHF (ANOVA, P < 0.05). The levels of global DNA methylation were significantly decreased by DEB treatment in a dose-dependent manner within each 5-MTHF concentration in TK-6 cells (ANOVA, P < 0.01), and were significantly increased by 5-MTHF supplementation within each DEB concentration (ANOVA, P < 0.01). Conclusion We reported that folate metabolism could modify the association between BD exposure and chromosomal damage, and such effect may be partially mediated by DNA hypomethylation, and 5-MTHF supplementation could rescue it.

scholarly journals Methylenetetrahydrofolate reductase gene polymorphism, global DNA methylation and blood pressure: a population based study from North India

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Suniti Yadav ◽  
Imnameren Longkumer ◽  
Shipra Joshi ◽  
Kallur Nava Saraswathy
Keyword(s):  
Blood Pressure ◽  
Dna Methylation ◽  
Gene Polymorphism ◽  
Methylenetetrahydrofolate Reductase ◽  
Antihypertensive Drugs ◽  
Colorimetric Assay ◽  
North India ◽  
Global Dna Methylation ◽  
Dna Hypomethylation ◽  
Cross Sectional

Abstract Background Hypertension is a complex disorder affected by gene-environment interactions. Methylenetetrahydrofolate reductase (MTHFR) gene is one of the genes in One Carbon Metabolic (OCM) pathway that affects both blood pressure and epigenetic phenomenon. MTHFR C677T gene polymorphism leads to reduced methylation capacity via increased homocysteine concentrations. Global DNA methylation (5mC%) also gets affected in conditions such as hypertension. However, no study is found to understand hypertension in terms of both genetics and epigenetics. The present study aims to understand the relation between methylation, MTHFR C677T gene polymorphism and hypertension. It also tries to understand relation (if any) between methylation and anti-hypertensive drugs. Methods This is a cross-sectional study where data were collected from a total of 1634 individuals of either sex in age group 35–65 years. Hypertensives (SBP ≥ 140 mm Hg and DBP ≥ 90 mm Hg) (on treatment/not on treatment) and absolute controls were 236 (cases) and 307 (controls), respectively. All the samples were subjected to MTHFR C677T gene polymorphism screening (PCR–RFLP) and global DNA methylation assay (ELISA based colorimetric assay). Results of both the analyses were obtained on 218 cases, 263 controls. Results Median 5mC% was relatively lower among cases (p > 0.05) compared to controls, despite controlling for confounders (age, sex, smoking, alcohol, diet) (r2-0.92, p-0.08). Cases not on medication had significantly reduced 5mC% compared to controls (p < 0.05), despite adjusting for confounders (r2-0.857, p-0.01). Among cases (irrespective of treatment), there was a significant variation in 5mC% across the three genotypes i.e. CC, CT and TT, with no such variation among controls. Cases (not on medication) with TT genotype had significantly lower methylation levels compared to the TT genotype controls and cases (on medication) (p < 0.01). Conclusion Global DNA hypomethylation seems to be associated with hypertension and antihypertensive drugs seem to improve methylation. Hypertensive individuals with TT genotype but not on medication are more likely to be prone to global DNA hypomethylation. Important precursors in OCM pathway include micronutrients such as vitamin B-12, B-9 and B-6; their nutritional interventions (either dietary or supplement) may serve as strategies to prevent hypertension at population level. However, more epidemiological-longitudinal studies are needed for further validation.

Effect of acute hyperhomocysteinemia on methylation potential of erythrocytes and on DNA methylation of lymphocytes in healthy male volunteers

2005 ◽  
Vol 289 (4) ◽  
pp. F786-F792 ◽  
Author(s):  
R. Fux ◽  
D. Kloor ◽  
M. Hermes ◽  
T. Röck ◽  
B. Proksch ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Methylenetetrahydrofolate Reductase ◽  
Global Dna Methylation ◽  
Methyl Groups ◽  
Healthy Male ◽  
Dna Hypomethylation ◽  
Plasma Thcy ◽  
Acute Elevation ◽  
Total Homocysteine ◽  
Kinetics Of

Homocysteine is a precursor of S-adenosylmethionine (AdoMet) and a metabolite of S-adenosylhomocysteine (AdoHcy). The ratio of AdoMet to AdoHcy, defined as the methylation potential (MP), indicates the flow of methyl groups within the cells. Chronic elevations of total homocysteine (tHcy) in plasma correlate with increased AdoHcy concentrations, decreased MP, and impaired DNA methylation. However, the influence of acute hyperhomocysteinemia on MP is unknown. We induced acute hyperhomocysteinemia in 14 healthy volunteers by oral administration of l-homocysteine (65.1 μmol/kg body wt) in an open, randomized, placebo-controlled two-period crossover study. The kinetics of tHcy in blood and urine, MP in blood, and global DNA methylation in lymphocytes were studied systematically during 48 h. Plasma tHcy concentrations reached a peak at 34 ± 11 min after an oral load with l-homocysteine and decreased with a half-life of 257 ± 41 min (means ± SD). Only 2.3% of the homocysteine dose were recovered in urine. AdoHcy concentrations and MP in whole blood and erythrocytes were not affected by the oral homocysteine load. Furthermore, global DNA methylation in lymphocytes did not change under these conditions. We found no difference between the genotypes of 5,10-methylenetetrahydrofolate reductase in response to the homocysteine load. However, AdoMet content in erythrocytes was significantly higher in the C677T carriers (CT; n = 7) compared with the CC genotype ( n = 7). Although chronic elevation of tHcy has been shown to affect MP and DNA methylation, acute elevation of plasma tHcy above 20 μmol/l for 8 h is not sufficient to change MP and to induce DNA hypomethylation in lymphocytes.

scholarly journals Artificial Light at Night of Different Spectral Compositions Differentially Affects Tumor Growth in Mice: Interaction With Melatonin and Epigenetic Pathways

2018 ◽  
Vol 25 (1) ◽  
pp. 107327481881290 ◽  
Author(s):  
A. E. Zubidat ◽  
B. Fares ◽  
F. Fares ◽  
A. Haim
Keyword(s):  
Breast Cancer ◽  
Dna Methylation ◽  
Tumor Growth ◽  
Short Wavelength ◽  
Global Dna Methylation ◽  
Artificial Light ◽  
Dna Hypomethylation ◽  
Light At Night ◽  
Cancer Burden ◽  
Melatonin Suppression

Lighting technology is rapidly advancing toward shorter wavelength illuminations that offer energy-efficient properties. Along with this advantage, the increased use of such illuminations also poses some health challenges, particularly breast cancer progression. Here, we evaluated the effects of artificial light at night (ALAN) of 4 different spectral compositions (500-595 nm) at 350 Lux on melatonin suppression by measuring its urine metabolite 6-sulfatoxymelatonin, global DNA methylation, tumor growth, metastases formation, and urinary corticosterone levels in 4T1 breast cancer cell-inoculated female BALB/c mice. The results revealed an inverse dose-dependent relationship between wavelength and melatonin suppression. Short wavelength increased tumor growth, promoted lung metastases formation, and advanced DNA hypomethylation, while long wavelength lessened these effects. Melatonin treatment counteracted these effects and resulted in reduced cancer burden. The wavelength suppression threshold for melatonin-induced tumor growth was 500 nm. These results suggest that short wavelength increases cancer burden by inducing aberrant DNA methylation mediated by the suppression of melatonin. Additionally, melatonin suppression and global DNA methylation are suggested as promising biomarkers for early diagnosis and therapy of breast cancer. Finally, ALAN may manifest other physiological responses such as stress responses that may challenge the survival fitness of the animal under natural environments.

scholarly journals Epigenome-wide DNA methylation and risk of breast cancer: a systematic review

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Kaoutar Ennour-Idrissi ◽  
Dzevka Dragic ◽  
Francine Durocher ◽  
Caroline Diorio
Keyword(s):  
Breast Cancer ◽  
Dna Methylation ◽  
Breast Cancer Risk ◽  
Cancer Risk ◽  
Risk Of Bias ◽  
Global Dna Methylation ◽  
Dna Hypomethylation ◽  
Epigenetic Age ◽  
Potential Biomarker

Abstract Background DNA methylation is a potential biomarker for early detection of breast cancer. However, robust evidence of a prospective relationship between DNA methylation patterns and breast cancer risk is still lacking. The objective of this study is to provide a systematic analysis of the findings of epigenome-wide DNA methylation studies on breast cancer risk, in light of their methodological strengths and weaknesses. Methods We searched major databases (MEDLINE, EMBASE, Web of Science, CENTRAL) from inception up to 30th June 2019, for observational or intervention studies investigating the association between epigenome-wide DNA methylation (using the HM450k or EPIC BeadChip), measured in any type of human sample, and breast cancer risk. A pre-established protocol was drawn up following the Cochrane Reviews rigorous methodology. Study selection, data abstraction, and risk of bias assessment were performed by at least two investigators. A qualitative synthesis and systematic comparison of the strengths and weaknesses of studies was performed. Results Overall, 20 studies using the HM450k BeadChip were included, 17 of which had measured blood-derived DNA methylation. There was a consistent trend toward an association of global blood-derived DNA hypomethylation and higher epigenetic age with higher risk of breast cancer. The strength of associations was modest for global hypomethylation and relatively weak for most of epigenetic age algorithms. Differences in length of follow-up periods may have influenced the ability to detect associations, as studies reporting follow-up periods shorter than 10 years were more likely to observe an association with global DNA methylation. Probe-wise differential methylation analyses identified between one and 806 differentially methylated CpGs positions in 10 studies. None of the identified differentially methylated sites overlapped between studies. Three studies used breast tissue DNA and suffered major methodological issues that precludes any conclusion. Overall risk of bias was critical mainly because of incomplete control of confounding. Important issues relative to data preprocessing could have limited the consistency of results. Conclusions Global DNA methylation may be a short-term predictor of breast cancer risk. Further studies with rigorous methodology are needed to determine spatial distribution of DNA hypomethylation and identify differentially methylated sites associated with risk of breast cancer. Prospero registration number CRD42020147244

Genetic polymorphisms of the enzymes involved in DNA methylation and synthesis in elite athletes

2011 ◽  
Vol 43 (16) ◽  
pp. 965-973 ◽  
Author(s):  
Ileana Terruzzi ◽  
Pamela Senesi ◽  
Anna Montesano ◽  
Antonio La Torre ◽  
Giampietro Alberti ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genetic Polymorphisms ◽  
Methylenetetrahydrofolate Reductase ◽  
Late Phase ◽  
Muscle Growth ◽  
Methionine Synthase ◽  
Control Group ◽  
Dna Hypomethylation ◽  
Methionine Synthase Reductase ◽  
Proliferation And Differentiation

Physical exercise induces adaptive changes leading to a muscle phenotype with enhanced performance. We first investigated whether genetic polymorphisms altering enzymes involved in DNA methylation, probably responsible of DNA methylation deficiency, are present in athletes' DNA. We determined the polymorphic variants C667T/A1298C of 5,10-methylenetetrahydrofolate reductase (MTHFR), A2756G of methionine synthase (MTR), A66G of methionine synthase reductase (MTRR), G742A of betaine:homocysteine methyltransferase (BHMT), and 68-bp ins of cystathionine β-synthase (CBS) genes in 77 athletes and 54 control subjects. The frequency of MTHFR (AC), MTR (AG), and MTRR (AG) heterozygous genotypes was found statistically different in the athletes compared with the control group ( P = 0.0001, P = 0.018, and P = 0.0001), suggesting a reduced DNA methylating capacity. We therefore assessed whether DNA hypomethylation might increase the expression of myogenic proteins expressed during early (Myf-5 and MyoD), intermediate (Myf-6), and late-phase (MHC) of myogenesis in a cellular model of hypomethylated or unhypomethylated C2C12 myoblasts. Myogenic proteins are largely induced in hypomethylated cells [fold change (FC) = Myf-5: 1.21, 1.35; MyoD: 0.9, 1.47; Myf-6: 1.39, 1.66; MHC: 1.35, 3.10 in GMA, DMA, respectively] compared with the control groups (FC = Myf-5: 1.0, 1.38; MyoD: 1.0, 1.14; Myf-6: 1.0, 1.44; MHC: 1.0, 2.20 in GM, DM, respectively). Diameters and length of hypomethylated myotubes were greater then their respective controls. Our findings suggest that DNA hypomethylation due to lesser efficiency of polymorphic MTHFR, MS, and MSR enzymes induces the activation of factors determining proliferation and differentiation of myoblasts promoting muscle growth and increase of muscle mass.

Global DNA methylation in the mouse liver is affected by methyl deficiency and arsenic in a sex-dependent manner

2010 ◽  
Vol 85 (6) ◽  
pp. 653-661 ◽  
Author(s):  
Keiko Nohara ◽  
Takashi Baba ◽  
Hikari Murai ◽  
Yayoi Kobayashi ◽  
Takehiro Suzuki ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Mouse Liver ◽  
Global Dna Methylation ◽  
Dependent Manner

scholarly journals Chrysin Modulates Aberrant Epigenetic Variations and Hampers Migratory Behavior of Human Cervical (HeLa) Cells

2022 ◽  
Vol 12 ◽  
Author(s):  
Ritu Raina ◽  
Abdulmajeed G. Almutary ◽  
Sali Abubaker Bagabir ◽  
Nazia Afroze ◽  
Sharmila Fagoonee ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Tumor Suppressor ◽  
Histone Modification ◽  
Hela Cells ◽  
Tumor Suppressor Genes ◽  
Methylation Status ◽  
Global Dna Methylation ◽  
Dependent Manner ◽  
Suppressor Genes ◽  
Protein Levels

Purpose: Plant-derived phytochemicals have shown epigenetic modulatory effect in different types of cancer by reversing the pattern of DNA methylation and chromatin modulation, thereby restoring the function of silenced tumor-suppressor genes. In the present study, attempts have been made to explore chrysin-mediated epigenetic alterations in HeLa cells.Methods: Colony formation and migration assays followed by methylation-specific PCR for examining the methylation status of CpG promoters of various tumor-suppressor genes (TSGs) and the expression of these TSGs at the transcript and protein levels were performed. Furthermore, global DNA methylation; biochemical activities of DNA methyltransferases (DNMTs), histone methyl transferases (HMTs), histone deacetylases (HDACs), and histone acetyl transferases (HATs) along with the expression analysis of chromatin-modifying enzymes; and H3 and H4 histone modification marks analyses were performed after chrysin treatment.Results: The experimental analyses revealed that chrysin treatment encourages cytostatic behavior as well as inhibits the migration capacity of HeLa cells in a time- and dose-dependent manner. Chrysin reduces the methylation of various tumor-suppressor genes, leading to their reactivation at mRNA and protein levels. The expression levels of various chromatin-modifying enzymes viz DNMTs, HMTs, HDACs, and HATS were found to be decreased, and H3 and H4 histone modification marks were modulated too. Also, reduced global DNA methylation was observed following the treatment of chrysin.Conclusion: This study concludes that chrysin can be used as a potential epigenetic modifier for cancer treatment and warrants for further experimental validation.

scholarly journals Effects of Acute Benzo[a]pyrene Exposure on Blood Clam Tegillarca Granosa: Histological Changes, Oxidative Stress, Neurotoxicity and DNA Hypomethylation

2021 ◽  
Author(s):  
Baoying Guo ◽  
Dan Feng ◽  
Pengzhi Qi ◽  
Zhi Liao ◽  
Xiaojun Yan
Keyword(s):  
Oxidative Stress ◽  
Dna Methylation ◽  
Marine Pollution ◽  
Organic Pollutant ◽  
Global Dna Methylation ◽  
Dna Hypomethylation ◽  
Glutathione S Transferase ◽  
Histological Changes ◽  
Multiple Biomarkers ◽  
Blood Clam

Abstract The blood clam is being developed into a model bivalve molluscs for assessing and monitoring marine pollution on the offshore seabed. However, the information on the response of blood clam to PAHs, an organic pollutant usually deposited in submarine sediment, remains limited. Herein, we employed multiple biomarkers, including histological changes, oxidative stress, neurotoxicity and global DNA methylation, to investigate the effects of Bap exposure under laboratory conditions on blood clams and its potential mechanisms. Acute Bap exposure can induce significant morphological abnormalities in gills as shown through hematoxylin-eosin (H.E) staining, providing an intuitive understanding on the effects of Bap on the structural organization of blood clams. Meanwhile, the oxidative stress was significantly elevated as manifested by the increase of antioxidants activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and glutathione-s-transferase (GST), lipid peroxidation (LPO) level and 8-hydroxy-2’-deoxyguanosine (8-OHdG) content. The neurotoxicity was also strengthened by Bap toxicity manifested as inhibited acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities. In addition, the global DNA methylation level was investigated, and a significant DNA hypomethylation was observed in Bap exposed blood clams. The correlation analysis showed that the global DNA methylation was negatively correlated with antioxidants (SOD, CAT and POD) activities, but positively correlated choline enzymes (AChE and ChAT) activities. These results collectively suggested that acute Bap exposure can cause damage in gills structures in blood clams possibly by generating oxidative stress and neurotoxicity, and the global DNA methylation was inhibited to increase the transcriptional expression level of antioxidants genes and consequently elevate antioxidants activities against Bap toxicity. These results are hoped to shed some new light on the study of ecotoxicology effect of PAHs on marine bivalves.

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